Credit

Caption

Euglena gracilis. Light micrograph of a group of the single celled protozoa, Euglena gracilis. Euglenoids are common in ponds and stagnant fresh- water, with some species inhabiting brackish or marine environments. Coloured green, they contain chloroplasts (seen here) and obtain nourishment by the process of photosynthesis. They are thus found in the upper layers of the water column where light can penetrate. Euglena swims using a pair of hair-like flagellae. Magnification: x90 at 35mm size.